<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    
    <title>首页</title>
    <style>
         a {
            text-decoration: none;
            color: black;
            font-size: 18px;
        }

        h3 {
            width: 180px;
            height: 38px;
            margin: 200px auto;
            text-align: center;
            line-height: 38px;
            background: deepskyblue;
            border-radius: 5px;
        }
    </style>
</head>
<body>
    <h3>
        <a>Hello World!</a>
    </h3>
</body>
</html>